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Exp Clin Endocrinol Diabetes 1996; 104(2): 164-171
DOI: 10.1055/s-0029-1211439
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© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Cholecystokinin octapeptide and the daily rhythm of vasopressin and oxytocin release

J. Morawska-Barszczewska, J. W. Guzek, J. Kaczorowska-Skóra*
  • Department of Pathophysiology, Institute of Physiology and Biochemistry, Medical University of Lodz, Poland
  • * Department of Physiology, Institute of Physiology and Biochemistry, Medical University of Lodz, Poland
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Publication History

Publication Date:
15 July 2009 (online)

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Summary

The daily rhythm of neurohypophysial hormone release was monitored in rats given intracerebrov-entricularly (i.e.v.) CCK-8 (50 ng/10 μl — once daily over five days). In animals injected i.e.v. with vehicle solution (0.9% NaCl) plasma oxytocin and vasopressin concentrations were seen to rise significantly over the hours of daylight, decreasing during the night. The changes seen in the neurohypophysial vasopressin and oxytocin content were inversely related to the plasma concentrations. Under i.e.v. treatment with CCK-8, the daily rhythm of the vasopressin and oxytocin release was similar to daily rhythm in the control group; respective figures were, however, reduced for the hypothalamus and neurohypophysis as well as increased for the blood plasma.

It is suggested that CCK-8 may be involved in some circadian regulatory processes related to vasopressin and oxytocin release from the rat hypothalamo-neurohypophysial system.

Key words

Vasopressin - oxytocin - CCK-8 - daily rhythms